string=('他问，你知道cba是什么单词的缩写吗?')
print(string)
print('1.删除空格')
print('2.英文标点的替换')
print('3.首字母大写')
print('4.退出')
while True:
   option=input("请输入功能选项:ln")
   if option=='1':
      string = string. replace(',',',')
      print(string)
   elif option =='2':
      for i in string:
       if i==',':
          string-string. replace (',',',')
       elif i=='.':
          string- string.replace ('.','。')
       elif i=='?':
          string-string. replace ('?','?')
       elif i=='?':
          string - string. replace ("'","‘")
      string =string
      print(string)
   elif option =='3':
    string - string.upper()
    print(string)
   elif option =='4':
        break